1. Field of the Invention
The present invention relates to a broadcasting type information providing system which permits an information collecting device mounted on a moving body to obtain information stored in an information providing center via a communication line and a broadcasting line, and to the information collecting device mounted on a moving body, in particular, a travel environment information collecting device which efficiently transmits travel environment information such as traffic jam to a predetermined station such as an information providing center.
2. Conventional Art
A device which provides a variety of information to a moving body or vehicle so as to enhance comfort and safety in the moving vehicle is now being developed. A typical device of such devices is a car navigation system which calculates the shortest route to a destination by making use of such as map information and guidance information stored in the moving vehicle and navigates the same with such as a displayed map and voices. In such car navigation system, the map information and guidance information are stored in a large capacity memory medium such as CD-ROM and DVD. Although the information volume stored in such memory medium is enormous, the information is static one so that a dynamic information such as vacancy information in a parking lot, road traffic jam information and road condition information including an obstacle on the road at a desired moment can not be provided to a driver.
On one hand, recently a moving body communication device such as a portable phone and PHS is rapidly spreading, and a broad communication network including moving bodies is being established.
In one of already established examples of such system which permits to provide such dynamic information, an information service center is provided, and a user accesses the information service center via such as a portable phone or PHS installed in the moving body and obtains desired information via a communication line. The obtained information is displayed as image information on a display provided in a navigation device or is transferred to a driver via a voice synthesizer.
Although through the use of the above referred to moving body communication device the dynamic information can be provided to a user in a moving body as has been explained above, there arose the following problems.
Firstly, the capacity of the communication line is small. The digital data transferring speed for the portable phone and PHS which is now reduced into practice is from 9.6 KBPS to 32 KBPS, therefore, when communicating image information, it takes about 10 sec. for transmitting one screen image which deteriorates the response characteristic.
Secondly, a cost incurred for the communication is high. Further, since the communication cost is proportional to the communication time, when communicating image information, the communication time prolongs as has been explained above to increase the communication cost.
Thirdly, communication quality during moving is poor. This is caused by such as fading generated in the communication path, and the communication speed decreases in proportion to increase of bit error rate in the communication line and in the worst case the communication will be interrupted.
As a method of resolving the above problems, a method is studied in which dynamic information is transferred to a driver via a digital broadcasting line having a further higher quality as disclosed in Christer Grewin, xe2x80x9cAudio Quality vs. Data Servicesxe2x80x94a Possible Conflict?xe2x80x9d (Third International Symposium on Digital Audio Broadcasting, Jun. 4-5, 1996. Montreux Switzerland). Although the digital broadcasting line is limited to a unidirectional data transmission from the side of a broadcasting station to a user, the digital broadcasting line has a communication capacity of several MBPS with regard to an audio line and of several tens MBPS with regard to animating image. Further, in order to apply a technology such as image compression the communication capacity is designed to meet the worst case.
Further, when the data compression rate is high, namely, such as when monotonous images continue and when static images are transmitted, the compression rate is inherently heightened, and a band which is not used for general broadcasting is generated in the communication band. Therefore, if the communication information from the information service center to the moving body is superposed on the empty band and a broadcast receiving device installed at the side of the moving body separates the communication information, information can be obtained via the communication line having a high speed and stability.
Further, as a system which provides dynamic information, a system is already in use in which a traffic stream volume is measured by making use of such as cameras, ultrasonic wave sensors and photo sensors disposed along roads to discriminate between traffic jamming and non-traffic jamming based on the measured volume, and the traffic information is provided to a moving body via a communication path including FM multiplex channel broadcasting and radio wavexe2x80xa2photo beacon. Further, another system is also practically used in which a plurality of photo beacons which enable bidirectional communication are disposed along roads and traffic jamming information is collected by measuring travel time of a moving body between the beacons disposed at the road side.
These systems collect traffic information in real time by making use of a variety of information collecting devices such as cameras, ultrasonic sensors and photo beacons disposed at the sides of roads.
Further, a still further system is disclosed in JP-A-5-151496 (1993) in which a moving body communication is used and traffic information collected by the moving body itself is transmitted to the side of an information providing center, and the information providing center determines traffic information such as traffic jam by collecting these respective traffic information.
In a moving body communication device, a specific cell where the moving body exists now is judged, and a communication is performed via a base station installed in the specific cell. In order to judge a specific cell where the moving body exists, periodical communication is performed between the terminal side of the moving body communication device and the base station side, and the specific cell where the terminal exists is judged.
On the other hand, even when information is transmitted via a broadcasting station, there is a problem that it has to be judged whether a moving body which receives information exists in a service area of the broadcasting station, and information has to be provided to the moving body from the broadcasting station of which service area covers the position where the moving body exists now.
Further, when obtaining information via broadcasting, there is another problem that waiting time until answer information is transmitted tends to be prolonged in comparison with when a bidirectional communication is used. This is because that an instance sometimes happens which requires a waiting time when superposing the answer information on general information, and because of existence of other users the broadcasting line sometimes becomes crowded.
Still further, with regard to the broadcasting receiving device, except when a user is receiving the broadcasting, the power source therefor is turned off. Accordingly, there arises further problem that it is necessary to turn on and off the power source by a proper measure depending on necessity.
With regard to the above explained method in which the traffic information is collected by making use of such as photo beacons, since it is necessary to dispose sensors along the road sides, an enormous number of ultrasonic wave sensors and photo sensors is necessitated depending on number of roads which incurs substantial investment cost. Further, with the ultrasonic wave sensors and the photo sensors, basically only information is obtained with regard to vehicles which have passed under these sensors, therefore, information generated in a region between sensors can not be obtained. Further, it is of course true that no information can not be obtained for regions where no sensors are disposed.
On the other hand, with regard to the method in which through the use of the moving body communication the traffic information collected by the moving body is transmitted to the information providing center, it is possible to resolve the problem encountered in the above beacon method, however, in order to maintain newness of the collected information it is necessary to frequently transmit collected information to the side of the information center which increases communication cost and, resultantly, causes disadvantage of service fee increase to users.
Still further, in order to fulfill accuracy, reliability and real time characteristics of the traffic information it is necessary to obtain traffic information at the same time from a predetermined number of moving bodies, therefore, there is another problem that if a substantial number of terminals is not prepared at the information providing center, the communication line overflows.
An object of the present invention is to provide a broadcasting type information providing system which resolves the above problems.
Another object of the present invention is to provide a broadcasting type information providing system which can operate so as to provide answer information to a user while selecting an optimum communication route and an optimum broadcasting station.
Still another, object of the present invention is to provide a travel environment information collecting device mounted on a moving body for collecting travel environment information which permits reduction of communication traffic when transmitting collected information to the side of an information center.
A further object of the present invention is to provide an information providing system being provided with an information center which stores information from travel environment information collecting devices mounted respectively on a plurality of moving bodies and transmits the stored information to the respective moving bodies, and which information providing system permits efficient collection of road environment information through further limited communication by controlling the transmission timing of the road environment information collected by the respective moving bodies to the side of the information center.
A broadcasting type information providing system including a moving body side device mounted on a moving body and an information providing side device for providing information to the moving body side device according to the present invention which achieves the above objects, is characterized in that the moving body side device comprises a moving body side communication means which performs bidirectional communication with the information providing side device; an information requesting means which transmits request information representing request contents of a user to the information providing side device via the moving body side communication means; a receiving means which receives answer information with respect to the request information being transmitted from the information providing side device; and an information presenting means which presents the received answer information to the user, and in that the information providing side device comprises a first information providing side communication means which performs bidirectional communication with the moving body side communication means; an answer information editing means which generates answer information to the request information transmitted from the moving body via the first information providing side communication means; a second information providing side communication means which performs communication with a broadcasting installation performing broadcasting for a specific service area so as to transmit the answer information to the moving body; and a control means which selects a broadcasting installation of which service area includes a position at which the moving body receives the answer information based on the position information of the moving body detected either by the moving body side device or by the information providing side device, transmits the answer information to the selected broadcasting installation via the second information providing side communication means and causes to broadcast the answer information from the selected broadcasting installation, whereby the broadcasting type information providing system operates so that an optimum broadcasting station is selected depending on the position of the moving body, thereby information can always be received under an optimum condition.
Further, in the broadcasting type information providing system according to the invention which achieves the above objects, it is possible to modify the system in such a manner that predetermined items with regard to generation and transmission of the answer information are evaluated and when transmitting the answer information it is determined whether the answer information be transmitted via the first information providing side communication means or via the selected broadcasting installation depending on the evaluation result of the predetermined items. Herein, as the evaluation items it is preferable to use at least one of a crowded degree of broadcasting signals in the broadcasting installation in which the answer information is to be broadcasted, a communication speed between the information providing side communication means and the moving body side communication means, data volume in the answer information, a required time for generating the answer information and a time dependency of the answer information. Thereby, a user can obtain the answer information via an optimum communication route.
A broadcasting type information providing system including a moving body side device mounted on a moving body and an information providing side device for providing information to the moving body side device according to the present invention which achieves the above objects, is characterized in that the moving body side device comprises a moving body side communication means which performs bidirectional communication with the information providing side device; an information requesting means which transmits request information representing request contents of a user to the information providing side device via the moving body side communication means a broadcast receiving means which receives answer information with respect to the request information being broadcasted from the information providing side device; and an information presenting means which presents the received answer information to the user, and in that the information providing side device comprises a first information providing side communication means which performs bidirectional communication with the moving body side communication means; an answer information editing means which generates answer information to the request information transmitted from the moving body via the first information providing side communication means; and a broadcasting means for transmitting the answer information to the moving body, and is further characterized in that the moving body side device further comprises a device control means for controlling the broadcast receiving means so as to receive broadcasting of the answer information by the broadcasting means, wherein the device control means, for example, performs on and off of a power source and changing-over of receiving channels for the broadcast receiving means depending on broadcast schedule of the answer information which is to be transmitted via the moving body side communication means.
A travel environment informations collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises a collecting means which collects travel environment information of a road on which the vehicle concerned is travelling; a receiver means which receives travel environment information being transmitted from an information center which stores in advance travel environment information; a judgement means which judges whether a processing of updating or new generation for a part of the received travel environment information is necessary by making use the collected travel environment information; and a transmitting means which transmits the travel environment information collected by the collecting means and to be used for the concerned processing to the information center when the judgement means judges that either the updating processing or the new generation processing is necessary.
The above travel environment information collecting device according to the present invention may further comprise a position measurement means which measures the position of the vehicle, wherein the judgement means retrieves travel environment information corresponding to the measured position depending on the measured position information and the received travel environment information, compares the retrieved result and the collected travel environment information and judges the necessity of the updating processing or the new generation processing based on the comparison result.
Further, a travel environment information collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises: a collecting means which collects travel environment information of a road on which the vehicle concerned is travelling; a receiver means which receives travel environment information being transmitted from outside; a comparison means which compares the collected travel environment information with the travel environment information corresponding to the collected travel environment information among the received travel environment information; and a transmitter means which transmits the travel environment information collected by the collecting means to an information center installed in the outside when the two travel environment informations compared in the comparison means are judged different.
Further, a travel environment information collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises: a collecting means which collects travel environment information of a road on which the vehicle concerned is travelling; a receiver means which receives travel environment information being transmitted from outside; a judgement means which judged whether information relating to the road on which the vehicle concerned is now travelling is included in the received travel environment information; and a transmitting means which, when the judgement means judges that the information relating to the road on which the vehicle concerned is now travelling is not included in the received travel environment information, transmits the travel environment information collected by the collecting means with regard to the road region which is judged not included in the received travel environment information to an information center installed in the outside.
Further, a travel environment information collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises: a collecting means which collects travel environment information of a road on which the vehicle concerned is travelling; an environmental change judgement means which judges whether an environment change has happened for the vehicle concerned; and a transmitting means which transmits the collected travel environment information to an information center installed in the outside when the environment change judgement means judges the travel environment has changed.
In the above travel environment information collecting device according to the present invention, it is preferable that the travel environment information collected by the collecting means includes at least one of, for example, traffic jamming information, road condition information and weather information. Still further, the travel environment information collecting device according to the present invention further comprises a position measurement means which measures the position of the vehicle concerned and wherein the travel environment information collected by the collecting means includes position information with respect to the position where the travel environment information is collected and time information with regard to the time when the travel environment information is collected.
Further, a travel environment information collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises: a position measuring means which measures the position of the vehicle concerned; a traffic jam information collecting means which collects traffic jam information representing whether the road on which the vehicle concerned is now travelling is traffic-jamming; and a transmitting means which transmits the traffic jam information and the position information representing the position of the vehicle concerned which is measured by the position measurement means to an information center installed in the outside, when the traffic jam information collected by the traffic jam information collecting means changes from non-traffic jamming to traffic jamming.
Further, a travel environment information collecting device mounted on a vehicle according to the present invention which achieves the above objects comprises: a collecting means which collects travel environment information of a road on which the vehicle concerned is travelling; a transmitting means which transmits an information retrieval request to an information center installed in the outside of the vehicle concerned; and a receiving means which receives answer information with respect to the information retrieval request being transmitted from the information center, wherein the transmitting means transmits the travel environment information collected by the collecting means together with the information retrieval request to the information center, and further the travel environment information collecting device may further comprise a transmission control means which limits transmitting information volume of the travel environment information so that the transmission of the travel environment information collected by the collecting means is completed until the reception of the answer information with regard to the information retrieval request being transmitted from the information center is completed.
Still further, an information providing system comprising a travel environment information collecting device mounted on a vehicle which collects information relating to travel environment of a road on which the vehicle concerned is travelling and an information center which stores information relating to travel environment as well as provides the stored travel environment information to vehicles according to the present invention which achieves the above objects, is characterized in that the travel environment information collecting device comprises: a collecting means which collects travel environment information of the road on which the vehicle concerned is now travelling; a receiving means which receives travel environment information being transmitted from the information center; a judgement means which judges whether a processing of updating or new generation for a part of the received travel environment information is necessary by making use the collected travel environment information; and a transmitting means which transmits the travel environment information collected by the collecting means and to be used for the concerned processing to the information center when the judgement means judges that either the updating processing or the new generation processing is necessary, and in that the information center comprises: a memory means which stores the travel environment information; a transmitting means at the side of the information center which transmits the stored travel environment information; a receiving means at the side of the information center which receives the travel environment information being transmitted from the travel environment information collecting device; and an updating means which updates or newly generates at least a part of the travel environment information stored in the memory means by making use of the received travel environment information.